Databases can be used to store many data values. But sometimes it is helpful to have a more bird's eye view of the data that is provided. With data aggregation, thousands or even millions of database records can be aggregated or viewed in a summary form to provide a different view of the stored data. But the data aggregation process often consumes a great deal of memory, especially as the number of stored database records grow. Specifically, the data aggregation process often produces intermediate results which consume a great deal of memory prior to producing the final aggregated result. This is often problematic for in-memory database systems because queries may have to be aborted when the system runs out of memory, or new queries may not be admitted for processing because not enough free memory is available for their execution.
In the drawings, like reference numbers generally indicate identical or similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.